National Center for Atmospheric Research Uncovers Growing Risk of a Fire Age: Doubling CO2 Equals More Than 7 Degrees of Warming

A study released last week from the National Center for Atmospheric Research (NCAR) showed that for each doubling of atmospheric CO2 content, the Earth’s climate warms by about 7-8 degrees Fahrenheit or around 4.5 degrees Celsius. The authors, John Fasullo and Kevin Trenberth found that the models predicting the greatest degree of warming were the most accurate. These models took into account the complex interplay of cloud formation and increasing levels of atmospheric water vapor due to heating.

This study’s findings more closely parallel indications seen in the geological record where CO2 doublings pushed temperature warming in the range of 5-6 degrees Celsius or more. It is also another indicator that persistent CO2 at current levels of near 400 ppm are enough to push global warming above the, very dangerous, 2 degree threshold. In fact, geological evidence has pointed to recent periods in Earth’s past when 400 ppm CO2 resulted in temperatures 3-4 degrees Celsius hotter than they are now.

The study’s findings are important due to the fact that scientists believe very damaging climate impacts begin to occur at 2 degrees Celsius above the 20th century average. However, massive Arctic sea ice melt, expanding desertification, extreme fire seasons, extreme heat waves, and increasingly intense storms show that very damaging effects are beginning now, at just less than a 1 degree Celsius global temperature increase.

Fast forward to the end of the 21rst century and we, under business as usual fossil fuel emissions, find ourselves at 1,400 ppm CO2 or more. The NCAR study would indicate that average world temperatures under such a situation will increase by 12-15 degrees Celsius. This massive temperature increase would be three times that of the difference between the current age and an ice age — but on the side of hot. An extreme fire age, if you will. This potential is also three times the current maximum temperature increase predicted in the most recent IPCC model scenarios.

Given this prospect and the growing clarity coming from climate model analysis, it is becoming ever more obvious that our fossil fuel consumption has already burned us out of the safe zone and is increasingly pushing us into a dangerous era of devastating climate impacts. A recent Discovery Magazine article analyzing the NCAR report somewhat joking called for climate change alarmism in an article entitled: Wanted: Global Warming Alarmists.

And it is true that global warming alarmism is indeed called for because, well, the world need a proper warning for what’s in store. Especially if we continue to subsidize fossil fuel production to the tune of half a trillion dollars each year and growing.

4 Comments

jyyh

I believe the increased storms, droughts and whatnot is partly an inherent feature of a climate system in state of change. The atmosphere that responds to ghgs immediately starts to expand and behave differently from previous times, whereas the ocean features lag in their expected behaviour on selected ghg levels. Thus one might argue the atmosphere is trying to do things that the hydro-(well also cryo-)sphere is not yet allowing. This would create ‘never-before-seen’ combinations of coupled ocean-atmosphere systems. So the increased extreme events would be partly because of the difference in the delays within earth, and not solely due increased ghgs. It’s the speed of change in one part of the system, that’s partly responsible, just like in ecological systems in change, where increasing the number of pests leads to increasing damage to the crop… I’m still of the opinion that 400ppm might be the limit for very dangerous effects, but have been forced to admit it causes at least +15 rise in sea level in the long run (but might be very fast), so to err on the safe side I could go with the 350ppm limit (with still some rise (3-6?)). quite a lot of people have been advocating.

350, if we could get there would be much better. Still puts us in or near the context of the Pliocene. So the bottom range of that sea level rise, long term, may still be in the cards. The other point to consider would be that a number of ice sheets are already destabilized and will collapse regardless. So that’s in the cards even in the best case.

A rapidly changing climate creates a high degree of instability. The Earth heats unevenly and ice melt/destabilization plays havoc with weather. And we may well be cramming an ice age to interglacial or more worth of climate change in one century. The weather, in such an event, could well be described as outside anything in the current context and probably anything within racial memory.